For those who found this post later, I developed my own solution. It seems that when the alex toolbar is installed, it appears in the user agent.
<?php echo $_SERVER['HTTP_USER_AGENT']; ?>
You can redirect these users with php
preg_match('/(Alexa)/i',$_SERVER['HTTP_USER_AGENT'])?header('Location: http://alexausersgohere.com'):null;
You can also just redirect them by dropping this into your .htaccess file.
Options +FollowSymlinks RewriteEngine On RewriteBase / RewriteEngine on RewriteCond %{HTTP_USER_AGENT} ^Alexa RewriteRule ^(.*)$ alexausersgohere.com#$1 [R=301,L]
Make sure you double check this htaccess code, I just wrote it as a demo, didn't test it, I used php.
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